Recording medium delivery mechanism and image forming device having the same

ABSTRACT

A recording medium discharge mechanism is provided with a side wall member capable of changing position between an upright state in which small size sheets are caught when small size sheets are discharged and a laid flat state in which a placement surface of a discharge space is extended for placement of large size sheets when large size sheets are discharged by a discharge mechanism having the discharge space, whose downstream side in a paper discharge direction has been opened. In the upright state, the side wall member does not protrude laterally from an apparatus. Furthermore, in the laid flat state, large size sheets can be placed.

This application is the US national phase of international applicationPCT/JP2004/005047 filed 7 Apr. 2004, which designated the U.S. andclaims priority to JP 2003-105431 filed 9 Apr. 2003, the entire contentsof each of which are hereby incorporated by reference.

TECHNICAL FIELD

The disclosed technology relates to recording medium dischargemechanisms that are installed in image forming apparatuses such ascopying machines, printers, and facsimile machines and to image formingapparatuses provided with such recording medium discharge mechanisms. Inparticular, the disclosed technology relates to internal discharge-typerecording medium discharge mechanisms in which the discharge portion forthe recording media is arranged in a substantially central portion inthe vertical direction of the apparatus.

BACKGROUND ART

Conventionally, it has been desired to reduce the installation space ofimage forming apparatuses such as copying machines, printers, andfacsimile machines, as well as compound machines that are provided witha plurality of these functions.

In response to this desire, image forming apparatuses have beendeveloped in which the feeding portion (paper cassette) is arranged in alower portion and the original capturing portion (scanner portion) isarranged in an upper portion, while the image forming portion (printerportion) and the discharge portion (discharge tray) are provided betweenthe feeding portion and the original capturing portion. That is, withthese image forming apparatuses, a reduction in the apparatusinstallation space is achieved by providing the discharge tray such thatit does not protrude laterally from the apparatus. Furthermore, withthese image forming apparatuses, the feeding portion, the originalcapturing portion, and the image-forming portion are arranged in anapproximate square-cornered reverse “C” shape when viewed from the frontof the apparatus. In this structure, the discharge portion is configuredas an empty intermediate space that opens laterally (one side of thesquare-cornered reverse “C” shape is open), and printed sheets that aredischarged to this empty intermediate space are taken out from the frontside or a lateral side (the above-mentioned open side).

However, with this type of image forming apparatus, since visibility ispoor for the printed sheets that are discharged to the emptyintermediate space, it has been a matter of concern that the userforgets to take out printed sheets or leaves some sheets behind.

Techniques are disclosed in JP H06-115794A (hereinafter referred to aspatent document 1) and JP H08-339107A (hereinafter referred to as patentdocument 2) as ways to solve this fault.

First, in patent document 1, a structure is disclosed in which arotational movement means is provided in a plurality of discharged paperpiling means (a unit of discharged paper trays) in order to achieveoverall space savings in an apparatus in which the discharge portiondoes not protrude from the apparatus. In this structure, after dischargeof the paper has been completed, the plurality of discharged paperpiling means are rotationally moved as a whole in a horizontaldirection.

On the other hand, in patent document 2, in order to improve visibilityof the printed sheets that are discharged to the discharge portion in animage forming apparatus provided with a so-called internaldischarge-type recording medium discharge mechanism in which only thefront side of the apparatus is open, a structure is disclosed that aimsto improve visibility of printed sheets by arranging an illuminatinglamp at an upper portion of an inner side of the discharge portion suchthat the illuminating lamp is caused to automatically light up when thedischarge of a printed sheet is detected.

However, there is a limit to the device miniaturization that can beachieved with either of these patent documents, and both involveincreased complication of control operations by a control portion. Thatis, with these techniques, a space is required for the discharge portionthat is substantially equivalent to the size of the maximum length sheetof the plurality of sheet sizes that are used in the apparatus. Forexample, in an apparatus using an A3 size (297 mm×420 mm) sheet, 420 mmor more is required for the length of the discharge portion and since asize smaller than this size cannot be achieved, it is not possible toachieve further compactness. The reason for this is that when the spaceof the discharge portion is made smaller than the size of the maximumlength sheet, the sheets become folded over (so-called “back bending”)inside the discharge portion in these internal discharge-typeapparatuses, thus posing the risk of frequent paper jams.

The embodiments of the present invention have been devised inconsideration of these issues, and it is an object thereof to provide arecording medium discharge mechanism that is provided with a dischargespace into which a recording medium that has undergone image formationis discharged and that is capable of achieving device compactness andcontrol operation simplification, and an image forming apparatusprovided with the recording medium discharge mechanism.

SUMMARY

In order to achieve the above-mentioned object, an embodiment of thepresent invention is provided with a member capable of changing positionbetween an upright state in which small size sheets are caught whensmall size sheets are discharged and a laid flat state in which aplacement surface of a discharge space is extended for placement oflarge size sheets when large size sheets are discharged by a dischargemechanism having the discharge space whose downstream side in a paperdischarge direction has been opened. That is, the upright statecontributes to reductions in the installation space of image formingapparatuses by the fact that this member does not protrude laterallyfrom the apparatus, and with the laid flat state it is possible toachieve placement of large size sheets while avoiding paper bending andpaper jams inside the discharge space.

Specifically, a recording medium discharge mechanism is provided with adischarge space that is positioned between an original capturing portionarranged in a device upper portion and a feeding portion arranged in adevice lower portion and that opens laterally to a downstream side in arecording medium discharge direction. In this recording medium dischargemechanism, a side wall member is arranged at an open portion of thedownstream side in the recording medium discharge direction. Also, theside wall member is configured to be capable of moving between anupright state that closes the open portion and a laid flat state inwhich a placement surface for placing a discharged recording medium isextended toward the downstream side in the recording medium dischargedirection. It should be noted that “placement surface for placing adischarged recording medium” refers to a surface that spans from therecording medium placement surface, which is the bottom surface of theabove-mentioned discharge space, to an upper surface of the side wallmember in the laid flat state (a surface substantially linked to theabove-mentioned recording medium placement surface).

With this specified item, the side wall member becomes upright andcloses the open portion when the discharge direction length of therecording medium to be used in image formation is the same length orshorter than the bottom surface of the discharge space for example. Thisenables the recording medium that is discharged to the discharge spaceto be caught by the side wall member even when the recording medium isdischarged at a comparatively high speed, and the recording medium doesnot drop from the discharge space. On the other hand, when the dischargedirection length of the recording medium used in image formation islonger than the recording medium discharge direction length of thebottom surface of the discharge space, the side wall member becomes laidflat such that the above-described open portion is opened and theplacement surface for placing the recording media that are dischargedextends toward the downstream side of the recording medium dischargedirection. This enables lengthy recording media to be placed extendingfrom the bottom surface of the discharge space over the upper surface ofthe side wall member, which makes it possible to avoid paper bending andpaper jams inside the discharge space and prevents dropping of therecording media from the discharge space. By providing the side wallmember that is capable of moving between the upright state and the laidflat state as described above, the position of the edge of one end ofthe image forming apparatus may be set at the position of the side wallmember in the upright state, and large size sheets can be held withoutdropping even without extending this laterally from the position of theside wall member. Thus, it is possible to achieve compactness in theinstallation space of the apparatus. Furthermore, it is sufficient toprovide only a mechanism for changing the position of the side wallmember, and it is unnecessary to provide a mechanism for horizontallyrotating the discharged paper collection means as is done conventionallyor to carry out ON/OFF control of a lighting lamp, and therefore controloperation can be simplified.

Specific dimensions of the above-mentioned discharge space are givenbelow. Namely, the recording medium placement surface, which is a bottomsurface of the discharge space, is set such that a discharge directionlength thereof is shorter than a discharge direction length of a largestrecording medium among a plurality of types of recording media used inan image forming apparatus.

With this specified item, at least when carrying out image formation ona recording medium having the maximum discharge direction length, theside wall member becomes laid flat such that the above-described openportion is opened and the placement surface for placing the recordingmedia is extended toward the downstream side of the recording mediumdischarge direction. That is, it becomes possible to provide a dischargespace in an image forming apparatus in which the discharge directionlength is shorter than the maximum discharge direction length of therecording medium, thereby realizing reductions in installation space.

Furthermore, the following is offered as a structure by which switchingbetween the upright state and the laid flat state is achieved for theside wall member. Namely, the side wall member is configured such thatwhen a recording medium has been discharged to the discharge space inthe upright state in which the open portion is closed by the side wallmember, the upright state changes to the laid flat state only uponreceiving an external force from the recording medium.

For example, a configuration is possible in which a biasing means (acoil spring or the like) is provided that applies a biasing force on theside wall member to the upright state side, and by setting this biasingforce low, the side wall member can be made to easily go into the laidflat state by the external force received from the recording medium whenthe recording medium is discharged. Then, due to the biasing force ofthe biasing means, the side wall member again becomes upright and doesnot protrude once the recording medium is removed from the dischargespace, thus contributing to compactness of the installation space of theapparatus. With this structure, the above-described switching operationcan be realized without necessitating a special drive source forswitching between the upright state and the laid flat state of the sidewall member. It should be noted that the recording medium dischargespeed or the recording medium hardness for making the side wall membergo into a laid flat state are determined by appropriately setting thebiasing force of the above-mentioned biasing means.

Furthermore, the side wall member is configured to go into the laid flatstate prior to a discharge operation of a recording medium only when adischarge direction length of the recording medium to undergo imageformation in an image-forming portion is longer than a length of arecording medium placement surface of the discharge space. For example,a drive source such as an actuator or a solenoid is provided to causerotation of the side wall member between the upright state and the laidflat state, and the drive source is driven in accordance to thedischarge direction length of the recording medium. This makes itpossible to avoid the end of the recording medium that is to bedischarged from colliding with the side wall member such that damage orthe like to the end of the recording medium can be reliably avoided.

More specific dimensions of these portions can be given in that, when arecording medium discharge direction length of a recording mediumplacement surface of the discharge space is given as L1, a dischargedirection length of a largest recording medium among a plurality oftypes of recording media used in an image forming apparatus is given asL2, and an extension length dimension toward a downstream side in therecording medium discharge direction of the paper placement surface whenthe side wall member has been put into the laid flat state is given asL3, the following is true:L3≦L2−L1.  (1).

With this specified item, when image formation is carried out on arecording medium of the maximum discharge direction length, the sidewall member becomes laid flat, but if the conditions of theabove-described relational expression are met, the position of the endportion of the recording medium at this time is a position protrudingslightly further than the end position of the side wall member. Thus, auser is able to easily take out the recording medium by gripping the endportion of the discharged recording medium, which enables improvedrecording medium withdrawal and obviates the side wall member being madelarger than necessary.

A material of the side wall member is given specifically as atransparent member or a semitransparent member. For example, the sidewall member may be constructed using an acrylic resin panel or the like.With this specified item, outside light passes through the side wallmember to illuminate the interior of the discharge space even when theside wall member is in the upright state, which achieves improvedvisibility for recording media that are discharged to the dischargespace even without using a special lighting apparatus and enablesprevention of the user forgetting to take out the recording media.

Furthermore, an image forming apparatus provided with an above-describedrecording medium discharge mechanism, an original capturing portionarranged at an upper portion of the recording medium dischargemechanism, and a feeding portion arranged at a lower portion of therecording medium discharge mechanism is within the scope of thetechnical idea of the present invention. The image forming apparatus ischaracterized by a configuration in which a side wall member is providedat an open portion of the downstream side in the recording mediumdischarge direction of the discharge space that is capable of movingbetween an upright state and a laid flat state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an outline of an internal configuration of a compoundmachine according to an embodiment of the present invention.

FIG. 2 shows an outline configuration of a paper discharge mechanism anda vicinity thereof.

FIGS. 3A, 3B and 3C show states in which various sheets are dischargedto a discharge space, with FIG. 3A showing a state in which sheets thathave a discharge direction length shorter than the length of the paperplacement surface have been discharged to the discharge space, FIG. 3Bshowing a state in which sheets that have a discharge direction lengthslightly longer than the length of the paper placement surface have beendischarged to the discharge space, and FIG. 3C showing a state in whichsheets, which have a discharge direction length longer than the lengthof the paper placement surface and have a maximum discharge directionlength, have been discharged to the discharge space.

FIG. 4 a and FIG. 4 b are outline configurations showing the side wallmember and a drive mechanism thereof in a modified example.

FIG. 5 is a flowchart showing a control operation procedure for changingthe position of the side wall member in the modified example.

DETAILED DESCRIPTION

Hereinafter, one or more embodiments of the present invention will bedescribed with reference to the accompanying drawings. The disclosedembodiment is described regarding a case in which the embodiment isapplied to a compound machine provided with a combination of a copyingfunction, a printing function, and a facsimile function.

—Description of the Overall Configuration of the Compound Machine—

FIG. 1 shows an outline of the internal structure of a compound machine1 as an image forming apparatus according to the embodiment. As shown inFIG. 1, the compound machine 1 is provided with a scanner portion 2 asan original capturing portion, a printing portion 3 as an image-formingportion, and an automatic original feeding portion 4. The following is adescription of the components therein.

The scanner portion 2 is a portion that reads images such as an image ofan original placed on an original stage 41 made of a material such astransparent glass and images of originals supplied sheet by sheet by theautomatic original feeding portion 4 and generates image data. Thescanner portion 2 is provided with an exposure light source 21, aplurality of reflectors 22, 23, and 24, an imaging lens 25, and a CCD(charge coupled device) 26.

The exposure light source 21 irradiates light toward an original placedon the original stage 41 of the automatic original feeding portion 4 ororiginals transported on the automatic original feeding portion 4. Thereflectors 22, 23, and 24 are configured such that, as with the lightpath shown by the dashed dotted line in FIG. 1, after light reflectedonce from the original is reflected in a leftward direction in thedrawing, it is reflected downwards, then reflected rightwards in thedrawing towards the imaging lens 25.

When an original is placed on the original stage 41 as an image readingoperation of the original (when used as a “fixed sheet system”), theexposure light source 21 and the reflectors 22, 23, and 24 scanhorizontally along the original stage 41 and read an image of the entireoriginal. On the other hand, when reading an original transported on theautomatic original feeding portion 4 (when used as a “sheet movementsystem”) the exposure light source 21 and the reflectors 22, 23, and 24are fixed in the position shown in FIG. 1, and the original capturingportion 42 of the automatic original feeding portion 4, which is to bedescribed later, reads the images while the original passes through.

The light that is reflected by the reflectors 22, 23, and 24 and passesthrough the imaging lens 25 is guided to a CCD 26, and the reflectedlight is transformed by the CCD 26 into an electric signal (originalimage data).

The printing portion 3 is provided with an image-forming system 31 and apaper transport system 32.

The image-forming system 31 is provided with a laser scanning unit 31 aand a photosensitive drum 31 b as a drum-type image carrier. Based onoriginal image data converted by the CCD 26, the laser scanning unit 31a irradiates a laser light onto a surface of the photosensitive drum 31b. The photosensitive drum 31 b rotates in the direction shown by thearrow in FIG. 1 and an electrostatic latent image is formed on thesurface thereof by the irradiation of laser light from the laserscanning unit 31 a.

Furthermore, in addition to the laser scanning unit 31 a, a developmentapparatus (development mechanism) 31 c, a transfer unit (transfermechanism) 31 d, a cleaning apparatus (cleaning mechanism) 31 e, anunshown charge removal unit, and a charging unit 31 f arecircumferentially arranged in order around the periphery of thephotosensitive drum 31 b. The development apparatus 31 c uses toner (asubstance for developing) to develop the electrostatic latent imageformed on the surface of the photosensitive drum 31 b into a developingimage. The transfer unit 31 d transfers the toner image formed on thesurface of the photosensitive drum 31 b to a sheet for image formation,which is a recording medium. The cleaning apparatus 31 e removes tonerthat is residual on the surface of the photosensitive drum 31 b aftertoner transfer. The charge removal unit removes electric charges thatare residual on the surface of photosensitive drum 31 b. The chargingunit 31 f charges the surface of the photosensitive drum 31 b to apredetermined electric potential prior to the forming of theelectrostatic latent image.

In this way, when forming an image on the sheet for image formation, thesurface of the photosensitive drum 31 b is charged to a predeterminedelectric potential by the charging unit 31 f and the laser scanning unit31 a irradiates a laser light onto the surface of the photosensitivedrum 31 b based on the original image data. After this, the developmentapparatus 31 c uses toner to develop a visible image on the surface ofthe photosensitive drum 31 b, and the toner image is transferred to thesheet for image formation by the transfer unit 31 d. Further still,after this, toner that is residual on the surface of the photosensitivedrum 31 b is removed by the cleaning apparatus 31 e and electric chargesthat are residual on the surface of the photosensitive drum 31 b areremoved by the charge removal unit. This completes one, cycle of anoperation of forming an image on a sheet for image formation (a printingoperation). By repeating this operation it is possible to carry outcontinuous image forming with respect to a plurality of sheets for imageformation.

On the other hand, the paper transport system 32 transports sheet bysheet sheets for image formation that are stored in a paper cassette 33as a paper storage portion, for image forming to be carried out by theimage-forming system 31 and also discharges sheets for image formationon which an image has been formed to a discharge tray 35 as a dischargeportion.

The paper transport system 32 is provided with a main transport path 36and a reverse transport path 37. One end of the main transport path 36is positioned in opposition to a discharge side of the paper cassette 33and another end is in opposition to the discharge tray 35. As for thereverse transport path 37, one end is connected to the main transportpath 36 upstream (lower side in the drawing) from the arranged positionof the transfer unit 31 d, and connected to the main transport path 36downstream (upper side in the drawing) from the arranged position of thetransfer unit 31 d.

A pickup roller 36 a that is semicircular in profile is arranged at anupstream end of the main transport path 36 (a portion facing a dischargeside of the paper cassette 33). The sheets for image formation stored inthe paper cassette 33 are able to be intermittently supplied to the maintransport path 36 sheet by sheet due to the rotation of the pickuproller 36 a.

Register rollers 36 d are arranged upstream from the arranged positionof the transfer unit 31 d in the main transport path 36. The registerrollers 36 d align the positioning of the toner image on the surface ofthe photosensitive drum 31 b and the sheet for image formation whiletransporting the sheet for image formation. A fixing device 39, which isprovided with a pair of fixing rollers 39 a and 39 b for fixing thetransferred toner image to the sheet for image formation using heat isarranged downstream from the arranged position of the transfer unit 31 din the main transport path 36. Further still, a discharge roller 36 efor discharging the sheets for image formation to the discharge tray 35is arranged at the downstream end of the main transport path 36.

A branch catch 38 is arranged at a connection position on an upstreamend of the reverse transport path 37 facing the main transport path 36.The branch catch 38 is configured to be freely rotatable around ahorizontal axis between a first position shown by a solid line in FIG.1, and a second position at which the reverse transport path 37 isreleased by rotating in a counterclockwise direction in the drawing fromthe first position. When the branch catch 38 is at the first position,the sheets for image formation are transported toward the discharge tray35, and when it is at the second position, the sheets for imageformation can be supplied to the reverse transport path 37. A transportroller 37 a is arranged at the reverse transport path 37 and when asheet for image formation is supplied to the reverse transport path 37(when a sheet for image formation is supplied to the reverse transportpath 37 by so-called switchback transport), the sheet for imageformation is transported by the transport roller 37 a, then the sheetfor image formation is reversed on an upstream side of the registerroller 36 d such that it is again transported in the main transport path36 toward the transfer unit 31 d. That is, it is handled such that imageformation can be carried out on the reverse side of the sheet for imageformation.

The following is a description of the automatic original feeding portion4. The automatic original feeding portion 4 is configured as a so-calledreversing automatic document (original) feeder. The automatic originalfeeding portion 4 can be used as a sheet movement system and is providedwith an original tray 43 as an original placement portion, anintermediate tray 44, an original discharge tray 45 as an originaldischarge portion, and an original transport system 46 that transportsoriginals between the trays 43, 44, and 45.

The original transport system 46 is provided with a main transport path47 for transporting originals placed on the original tray 43 to theintermediate tray 44 via the original capturing portion 42 or theoriginal discharge tray 45, and a secondary transport path 48 forsupplying originals on the intermediate tray 44 to the main transportpath 47.

An original pickup roller 47 a and a fielding roller 47 b are arrangedat an upstream end (a portion facing the discharge side of the originaltray 43) of the main transport path 47. A fielding board 47 c isarranged below the fielding roller 47 b and, due to the rotation of theoriginal pickup roller 47 a, one sheet of the originals on the originaltray 43 passes between the fielding roller 47 b and the fielding board47 c such that it is supplied to the main transport path 47. PS rollers47 e are arranged on the downstream side of the linking area between themain transport path 47 and the secondary transport path 48 (area B inthe drawing). The PS rollers 47 e regulate the leading edge of theoriginal and the image reading timing of the scanner portion 2 to supplyoriginals to the original capturing portion 42. That is, the PS rollers47 e temporarily stop the transport of the original in the state inwhich the original was supplied, and regulates this timing to supplyoriginals to the original capturing portion 42.

The original capturing portion 42 is provided with a platen glass 42 aand an original pressing board 42 b and, when an original supplied fromthe PS rollers 47 e passes through between the platen glass 42 a and theoriginal pressing board 42 b, light from the above-mentioned exposurelight source 21 passes through the platen glass 42 a and is irradiatedon the original. At this juncture, original image data is obtained bythe above-mentioned scanner portion 2. A biasing force is applied to theback surface (top surface) of the original pressing board 42 b by anunshown coil spring. In this way, the original pressing board 42 b makescontact against the platen glass 42 a with a predetermined suppressingforce, thus preventing the original from rising up from the platen glass42 a when the original passes through the original capturing portion 42.

Transport rollers 47 f and original discharge rollers 47 g are providedon a downstream side of the platen glass 42 a. An original that passesover the platen glass 42 a is discharged to the intermediate tray 44 orthe original discharge tray 45 via the transport rollers 47 f and theoriginal discharge rollers 47 g.

An intermediate tray undulation board 44 a is arranged between theoriginal discharge rollers 47 g and the intermediate tray 44. Theintermediate tray undulation board 44 a has its center of undulation atan edge area of the intermediate tray 44 and is able to undulate betweena position (hereinafter referred to as “position 1”) shown in thedrawing by a solid line and a position (hereinafter referred to as“position 2”) that is raised upwards from the position 1. When theintermediate tray undulation board 44 a is in the position 2, anoriginal discharged from the original discharge rollers 47 g iswithdrawn to the original discharge tray 45. On the other hand, when theintermediate tray undulation board 44 a is in the position 1, anoriginal discharged from the original discharge rollers 47 g isdischarged to the intermediate tray 44. When an original is dischargedto the intermediate tray 44, an edge of the original is put into asandwiched condition between the original discharge rollers 47 g, and byreversing the rotation of the original discharge rollers 47 g while inthis condition, the original is supplied to the secondary transport path48 and is again dispatched to the main transport path 47 via thesecondary transport path 48. The operation of reversing the rotation ofthe original discharge rollers 47 g is carried out by regulating thedispatch of the original to the main transport path 47 and the timing ofimage reading. In this way, an image on the reverse side of an originalcan be read by the original capturing portion 42.

—Description of the Basic Operation of the Compound Machine—

As an operation of the compound machine 1 configured as described above,firstly, when the compound machine 1 functions as a printer, print data(image data, text data, etc) that is sent from a host device such as apersonal computer is received and the received print data is temporarilystored in an unshown buffer (memory). Along with the storage of printdata to the buffer, print data is read out from the buffer in order and,based on the print data that is read out, an image is formed on a sheetfor image formation by an image forming operation of the above-describedprinting portion 3.

Furthermore, when the compound machine 1 functions as a scanner, thescanned image data of the original read by the above-described scannerportion 2 is temporarily stored in the buffer. Along with the storage ofscanned image data to the buffer, the scanned image data is sent fromthe buffer to the host device in order, and an image is displayed on adisplay or the like of the host device.

Further still, when the compound machine 1 functions as a copyingmachine, an image is formed on a sheet for image formation by an imageforming operation of the printing portion 3 based on the original imagedata that is read by the above-mentioned scanning function.

—Description of the Paper Discharge Mechanism—

Next, a paper discharge mechanism 7 is described as a recording mediumdischarge mechanism. The paper discharge mechanism 7 is provided withthe above-mentioned discharge tray 35 and a side wall member 71 that isarranged at an end portion that is downstream in the paper dischargedirection of the discharge tray 35.

The discharge tray 35 is provided with a paper placement surface 35 a asa recording medium placement surface that is a slanted surface slantingslightly upwards toward the downstream side of the paper dischargedirection. And the space above the paper placement surface 35 a is adischarge space C for collecting sheets after image formation. That is,in the compound machine 1, the scanner portion 2 and the automaticoriginal feeding portion 4 are arranged in an upper area, the papercassette 33 is arranged in a lower area, and the printing portion 3 isarranged on the right side half in the drawing between the scannerportion 2 and the paper cassette 33, such that the compound machine 1forms an approximate square-cornered reverse “C” shape when viewed fromthe front. Thus, the discharge space C is configured as an emptyintermediate space that opens laterally (one side of the square-corneredreverse “C” shape (facing left in FIG. 1) is open), and paper (printedsheets) that are discharged to the discharge space C are taken out fromthe front side or a lateral side (the above-mentioned open side) of thecompound machine 1.

It should be noted in regard to a specific dimension of the paperplacement surface 35 a of the discharge tray 35 that the lengthdimension of the paper placement surface 35 a in the paper dischargedirection (its dimension in the left to right direction in FIG. 1) isset shorter than the discharge direction length of the sheet having thelargest discharge direction length of the plurality of types of sheetsused in the compound machine 1 (for example shorter than A3 size whenthe compound machine uses B5, A4, B4, and A3 sheets).

The side wall member 71 is arranged at the open portion on thedownstream side of the paper discharge direction. Specifically, as alsoshown in FIG. 2 (an outline structural view of the paper dischargemechanism 7 and the surroundings thereof, the side wall member 71 isprovided at the downstream end portion of the discharge tray 35 in thepaper discharge direction and is rotatably supported to rotate around arotational axle extending in a horizontal direction perpendicular to thepaper discharge direction (vertical direction in the paper plane of FIG.1).

Furthermore, a coil spring 72 is arranged between the side wall member71 and a side surface of the compound machine 1 such that the biasingforce of the coil spring 72 is applied in a clockwise direction in thedrawing with respect to the side wall member 71. It should be noted thatthe rotational position of the side wall member 71 in the clockwisedirection is restrained to a position in which the side wall member 71becomes upright as shown in FIG. 1. For example, by providing a stopperthat restrains the rotational position of the side wall member 71 in theclockwise direction, or by making the lower end surface of the side wallmember 71 abut the paper placement surface 35 a of the discharge tray 35as shown in FIG. 2, the clockwise rotation thereof is restrained.

Furthermore, the coil spring 72 that is employed has a comparativelysmall biasing force and when the side wall member 71 receives theexternal force from a sheet discharged to the discharge space C, theside wall member 71 resists the biasing force of the coil spring 72 androtates easily in the counterclockwise direction shown in the drawing tobecome laid flat (the state of the provisional line in FIGS. 1 and 2).That is, in the event of a sheet being discharged to the discharge spaceC while the side wall member 71 is in an upright state, when thedischarge speed of the sheet is greater than a predetermined speed orthe hardness of the sheet is harder than a predetermined hardness, theside wall member 71 becomes laid flat due to the external force from thesheet, thereby opening the downstream side of the discharge tray 35 inthe paper discharge direction and lengthening the paper placementsurface 35 a toward the downstream side in the paper dischargedirection. It should be noted that the paper discharge speed or thepaper hardness for making the side wall member 71 go into a laid flatstate are determined by appropriately setting the biasing force of theabove-mentioned coil spring 72.

FIG. 3 show states in which various sheets are discharged to thedischarge space C. FIG. 3A shows a state in which sheets (B5 size sheetsfor example) that have a discharge direction length shorter than thelength of the paper placement surface 35 a have been discharged to thedischarge space C. In this case, the side wall member 71 maintains anupright state.

FIG. 3B shows a state in which sheets (B4 size sheets for example) thathave a discharge direction length slightly longer than the length of thepaper placement surface 35 a have been discharged to the discharge spaceC. In this case, the side wall member 71 receives the external forcefrom the sheets and becomes laid flat such that the sheets become placedextending from the paper placement surface 35 a over the upper surfaceof the side wall member 71.

Further still, FIG. 3C shows a state in which sheets (A3 size sheets forexample), which have a discharge direction length longer than the lengthof the paper placement surface 35 a and have the maximum dischargedirection length, have been discharged to the discharge space C. In thiscase too, the side wall member 71 receives the external force from thesheets and becomes laid flat such that the sheets become placedextending from the paper placement surface 35 a over the upper surfaceof the side wall member 71. Furthermore, in this case, as will bedescribed later, the position of the end portion of the sheets is aposition that protrudes slightly further than the end position of theside wall member 71, which is a state in which a user can easily takeout the sheets by gripping the end portion of the protruding sheets.

After the side wall member 71 has been laid flat in this way by sheetshaving been discharged to the discharge space C, due to the biasingforce of the coil spring 72, the side wall member 71 again becomesupright and does not protrude once the sheets are removed from thedischarge space C, thus contributing to compactness of the installationspace of the compound machine 1.

The size of the side wall member 71 is described here. When a lengthdimension of the paper placement surface 35 a of the discharge space Cin the paper discharge direction is given as L1, a length dimension inthe discharge direction of a sheet having the largest dischargedirection length of the plurality of types of sheets used in thecompound machine 1 is given as L2, and an extension length dimensiontoward a downstream side in the paper discharge direction when the sidewall member 71 has been laid flat is given as L3, the size of the sidewall member 71 is set such that the following is true:L3≦L2−L1  (1)

Due to this, when image formation is carried out on a sheet of themaximum discharge direction length, the side wall member 71 becomes laidflat, but the position of the end portion of the sheet at this time is aposition protruding slightly further than the end position of the sidewall member 71. Thus, a user is able to easily take out the sheet bygripping the end portion of the discharged sheet, which enables improvedsheet withdrawal and obviates the side wall member 71 being made largerthan necessary. Since the size of the side wall member 71 is set in thisway, the size of the side wall member 71 does not have to be a size bywhich the entire open portion of the discharge space C is closed duringthe upright state. That is, a height that enables the sheets that are tobe discharged to be caught is sufficient for the height for closing theopen portion of the discharge space C.

Furthermore, an acrylic resin is employed specifically as a material forthe above-described side wall member 71 and the entirety of the sidewall member 71 is transparent or semitransparent. Thus, outside lightpasses through the side wall member 71 to illuminate the interior of thedischarge space C even when the side wall member 71 is in the uprightstate, which achieves improved visibility by the user for sheets thatare discharged to the discharge space C even without using a speciallighting apparatus and enables prevention of the user forgetting to takeout the sheets.

Effect of the Embodiment

As described above, by providing the side wall member 71 at thedownstream end portion on the discharge tray 35 in the paper dischargedirection, the side wall member 71 maintains an upright state closingthe above-described open portion when the discharge direction length ofpaper used in image formation is the same or shorter than the paperdischarge direction length of the paper placement surface 35 a of thedischarge space C. This enables the paper that is discharged to thedischarge space C to be caught by the side wall member 71 and the paperdoes not drop from the discharge space C. On the other hand, when thedischarge direction length of paper used in image formation is longerthan the paper discharge direction length of the paper placement surface35 a of the discharge space C, the side wall member 71 becomes laid flatsuch that the above-described open portion is opened and the paperplacement surface 35 a, which is a lower surface of the discharge space,extends toward the downstream side of the paper discharge direction.This enables long sheets to be placed extending from the paper placementsurface 35 a of the discharge space C over the upper surface of the sidewall member 71, which makes it possible to avoid paper bending and paperjams inside the discharge space C and prevents the dropping of paperfrom the discharge space C.

By providing the side wall member 71 that is capable of moving betweenthe upright state and the laid flat state as described above, theposition of the edge of one end of the compound machine 1 may be set atthe position of the side wall member 71 in the upright state, and largesize sheets can be held without dropping even without extending thislaterally from the position of the side wall member 71. Thus, it ispossible to achieve compactness in the installation space of thecompound machine 1. Furthermore, it is sufficient to provide only amechanism for changing the position of the side wall member 71, and itis unnecessary to provide a mechanism for horizontally rotating thedischarged paper collection means as is done conventionally or to carryout ON/OFF control of a lighting lamp, and therefore control operationcan be simplified. In particular, with the structure of the presentembodiment, the above-described switching operation can be realizedwithout necessitating a special drive source for switching between theupright state and the laid flat state of the side wall member 71.

Modified Example

A modified example of the present invention is described next. Thisexample is a modified example of the structure for changing the positionof the side wall member 71. Since other portions of the configurationare the same as in the above-described embodiment, only the structurefor changing the position of the side wall member 71 is described here.

FIG. 4 is an outline structural view showing the side wall member 71arranged at a downstream end portion of the discharge tray 35 in thepaper discharge direction and a drive mechanism thereof. As shown in thedrawing, the side wall member 71 according to the present embodiment isprovided at the downstream end portion of the discharge tray 35 in thepaper discharge direction and is rotatably supported to rotate around arotational axle extending in a horizontal direction perpendicular to thepaper discharge direction (direction perpendicular to the paper surfaceof FIG. 4).

A solenoid 8 is mounted on a side surface of the compound machine 1 viaa mounting piece 81 as a drive mechanism for causing the side wallmember 71 to rotate between the upright state and the laid flat state. Atip of a rod 82 that extends from the solenoid 8 is linked to the sidewall member 71 so as to be relatively rotatable. Then, although the rodprotrudes such that the side wall member 71 is kept in the upright state(see FIG. 4A) when the current is turned off for the solenoid 8, the rod82 becomes inserted when the current is turned on for the solenoid 8such that the side wall member 71 goes into the laid flat state (seeFIG. 4B).

The operation for switching between times of current on and current offto the solenoid 8 is carried out corresponding to the type of paper tobe used. That is, current to the solenoid 8 is turned on to make the rod82 become inserted and thus make the side wall member 71 become laidflat only when the discharge direction length of the paper on whichimage formation is to be carried out in the printing portion 3 is longerthan the length of the paper placement surface 35 a of the dischargespace C. Specifically, the side wall member 71 is put into the laid flatstate prior to the operation of discharging the sheets. It should benoted that an operation for detecting the paper size may be bydetermining the paper size by paper size data in image information thathas been obtained, or by providing an optical sensor on the paper carrypath and identifying the paper size using this sensor.

FIG. 5 is a flowchart showing a control operation procedure for changingthe position of the side wall member 71 in the present example. Thecontrol operation is described below with reference to this flowchart.

First, in step 1, a request for printing is made to the compound machine1 and step 2 involves waiting for print processing conditions to beinputted. If no print processing conditions are inputted, then anotifying operation is carried out in step 3 to prompt the user to inputprint processing conditions.

When print processing conditions are inputted (“yes” determination atstep 2), then the procedure proceeds to step 4 and a determination ismade as to whether or not the printing paper in the printing conditionsis longer than the length of the discharge portion (the paper dischargedirection length of the paper placement surface 35 a). Then, if thisdetermination is “yes,” then a current to solenoid 8 is turned oncausing the rod 82 to become inserted, which puts the side wall member71 into the laid flat state (step 5). Then, when the rod 82 is fullyinserted and the operation of laying flat the side wall member 71 iscompleted (“yes” determination at step 6), print processing is carriedout (step 7) with respect to the paper.

After the executing of the print processing, image formation continuesin order while determining whether or not subsequent printing isrequired and when image formation for all the image data has beencompleted, a notifying operation is carried out in step 9 prompting theuser to take out the paper from the discharge tray 35.

Then, when the user takes out the paper from the discharge tray 35(“yes” determination at step 10), the power to the solenoid 8 isterminated to make the rod 82 protrude, thereby putting the side wallmember 71 into the upright state (step 11) and causing a “standby state”in which the compound machine waits for a subsequent printing request.

On the other hand, if the determination at step 4 is “no,” that is, ifthe printing paper in the printing conditions is the same or shorterthan the discharge length (paper discharge direction length of the paperplacement surface 35 a), then the current to the solenoid 8 is notturned on, that is, the side wall member 71 is maintained in an uprightstate and print processing is carried out on the paper (step 12). Then,after the executing of the print processing, image formation continuesin order while determining whether or not subsequent printing isrequired and when image formation for all the image data has beencompleted (“no” determination at step 13), the compound machine is putinto a “standby state” waiting for any subsequent printing.

As described above, with the structure of this example, it is possibleto put the side wall member 71 into the appropriate position (uprightstate for small size papers and laid flat state for large size papers)prior to paper being discharged to the discharge space C at the time ofan image formation operation, and when carrying out image formation onlarge size papers in particular, the end of the papers that aredischarged can be kept from colliding with the side wall member 71 suchthat damage or the like of the end of the papers can be reliablyavoided.

Other Embodiments

In the above-described embodiment and modified example, description wasgiven as applied to a multifunction type image forming apparatus(compound machine) 1 provided with functions of a combination of acopying machine, a printer, and a facsimile machine. However, theembodiments are not limited to this and may be applied to an imageforming apparatus provided with any one of these functions or adifferent image forming apparatus.

In the above-described embodiment and modified example, a gap was formedbetween the upper end of the side wall member 71 in the upright stateand the lower end of the scanner portion 2, but the size of the sidewall member 71 may be set so that no gap is formed between the upper endof the side wall member 71 and the lower end of the scanner portion 2,thereby improving the attractiveness of the apparatus.

Furthermore, in the above-described modified example, print processingwas set to commence after the operation for laying flat the side wallmember 71 was completed, but the print processing operation and theoperation for laying flat the side wall member 71 may be carried outconcurrently. That is, the operations may be controlled so that theoperation for laying flat the side wall member 71 is completed prior topaper being discharged to the discharge space C.

INDUSTRIAL APPLICABILITY

The embodiments are effective in image forming apparatuses having adischarge portion for printed sheets in an empty intermediate space of asquare-cornered reverse “C” shape. The embodiments contribute toreducing the installation space of image forming apparatuses by having aside wall member that does not protrude laterally from the apparatus,and is beneficial in that large size sheets can be loaded while avoidingpaper bending and paper jams inside the discharge space in the laid flatstate, thereby enabling compactness of installation space for imageforming apparatuses, and since it is unnecessary to provide a mechanismfor horizontally rotating the discharged paper collection means as isdone conventionally or to carry out ON/OFF control of a lighting lamp,simplification of control operation can be achieved.

Furthermore, it is beneficial in that when a transparent member or asemitransparent member is used for the side wall member, outside lightpasses through the side wall member to illuminate the interior of thedischarge space even when the side wall member is in the upright state,which achieves improved visibility of the recording media that aredischarged to the discharge space even without using a special lightingapparatus, thereby improving the ease of use of an image formingapparatus.

1. A recording medium discharge mechanism positioned between an original capturing portion arranged in a device upper portion and a feeding portion arranged in a device lower portion of an image forming apparatus, comprising: a recording medium placement surface being a bottom surface of a discharge space, the discharge space having an open portion laterally to a downstream side in a recording medium discharge direction and receiving the recording medium that has undergone image formation in an image-forming portion of the image forming apparatus, wherein a discharge direction length of the recording medium placement surface is shorter than a length of a paper cassette of the feeding portion arranged to hold one or more types of recording media used in the image forming apparatus; a side wall member being provided at the downstream end portion in the recording medium discharge direction of the recording medium placement surface, wherein the side wall member is rotatably supported to rotate around a rotational axle extending in a horizontal direction perpendicular to the recording medium discharge direction, and is capable of moving between an upright state that closes the open portion of the downstream side in the recording medium discharge direction in the discharge space and a laid flat state in which the placement surface for placing a discharged recording medium is extended toward the downstream side in the recording medium discharge direction; and a coil spring being provided between the side wall member and a side face of the image forming apparatus, the side face being located below the recording medium placement surface and continuing from the downstream end portion in the recording medium discharge direction of the recording medium placement surface, wherein the side wall member is arranged to receive a biasing force by the coil spring so as to rotate from the laid flat state to the upright state, and wherein the side wall member is configured to move from the upright state to the laid flat state against the biasing force by the coil spring only upon receiving an external force from the recording medium having a discharge speed greater than a predetermined speed or having a hardness greater than a predetermined hardness when the recording medium has been discharged to the discharge space in the upright state of the side wall member that closes the open portion, and the side wall member is also configured to move to the upright state with a lower end surface of the side wall member abutting on the recording medium placement surface due to the biasing force by the coil spring when the recording medium placed on the recording medium placement surface has been removed in the laid flat state of the side wall member.
 2. The recording medium discharge mechanism according to claim 1, which is configured such that, when the discharge direction length of the recording medium placement surface of the discharge space is given as L1, the length of the paper cassette of the feeding portion arranged to hold one or more types of recording media used in the image forming apparatus is given as L2, and an extension length dimension toward a downstream side in the recording medium discharge direction when the side wall member has been put into the laid flat state is given as L3, L3≦L2−L1.
 3. The recording medium discharge mechanism according to claim 1, wherein the side wall member is structured using a transparent member or a semitransparent member.
 4. An image forming apparatus comprising the recording medium discharge mechanism according to claim 1, an original capturing portion arranged at an upper portion of the recording medium discharge mechanism, and a feeding portion arranged at a lower portion of the recording medium discharge mechanism.
 5. The recording medium discharge mechanism according to claim 1, wherein the discharge space is formed interior to an image forming apparatus formed by the original capturing portion and the feeding portion.
 6. The recording medium discharge mechanism according to claim 1, wherein the discharge space is separate from an original discharge space of the original capturing portion into which originally scanned documents are discharged after being scanned. 